Acid treating for spray oil



March 7, 1961 M. GORDON ETAL ACID TREATING FOR SPRAY on.

Filed April 22, 1958 United States Patent ACID TREATING FOR SPRAY OIL Moses Gordon, Chicago, Ill., and Gordon D. Kerns, El Dorado, Kans., assignors to Standard @il Company, Chicago, Ill., a corporation of Indiana Filed Apr. 22, 1958, ser. No. 730,096

s claims. (ci. 24m- 190) This invention relates to the acid treating of petroleum oils and particularly to the preparation of oil suitable for plant spraying.

It is customary to dissolve insecticides into hydrocarbon oils as carriers for application of insecticides to plants and foliage. The hydrocarbon oil must be of such a character that little or no harm is done to the plant by the amounts of oil striking the plant. In general oils which are low in aromatic content are preferred for these purposes. Oils for plant spray use commonly have a specication directed to phytotoxic nature known as unsulfonated residue. This test is carried out by treating the oil to very severe conditions with sulfuric acid; the oil remaining lafter the test is called the unsulfonated residue. It is preferred that an oil have a residue of not less than 90 percent.

Oils of this type are obtained by sulfuric acid treating ofpetroleum oils particularly virgin petroleum oils. Conventional acid treating processes require very large amounts of sulfuric acid and generally have great diiculty in simultaneously .producing an o-il of the yproper unsulfonated residue content and color stability. These oils are .therefore rather expensive'by comparison With normal refining operations.

An Aobject ofthe invention isa process for producing petroleum -oils suitable for .plantspraying and as insecticide carriers. A` particular object is a continuous process for relatively cheaply obtaining a petroleum oil suitable for insecticide. carrierpurposes. `Other objects will become apparent inthe course ofthendetailed description.

The invention is 4described in connection with the annexed figure which forms `a part of this disclosure. It is heated with steam, the feed oil is heated to a temperature between about 150 F. and 170 F. The particular temperature is determined by the color and unsulfonatable residue requirement of the product oil, the amount of acid and type of acid used and also the total time of contacting with the acid. In this embodiment the oil Vlis. raised to a temperature of 160 F. The heated oil is passed from heater 13 by way of line 1d into chamber 16.

Sulfuric acid from source17 is passed by Way of line 13 into chamber 16 where the acid and the oil arev given preliminary intermingling. The sulfuric acid used in the process contains between about 96% and 100% by weight of sulfuric acid andthe remainder Water. In theA particular embodiment the sulfuric acid is of 98% strength. The sulfuric acid vis preferably new acid, so called white acid, however, recovered .acid commonly known as black lacid and particularly fortified spent sulfuric acidfrom butanealkylation may be used.

The amount ofacid used in the process is determined by the characteristics of the feed oil and the product oil as Well as temperature land time of treating. VIn general between about 1 and .1.5 pounds of acid are used per gallon of oil. The acid `usage, is calculated as 100% acid. With the oil of this embodiment the acid usage is about 1.1-1.2 pounds per gallon, depending on how closely the desired 160 F. treating temperature is maintained. The

to -be understood4 that the. figure kshowsa very schematic representationy of oneembodimentof the'process. Numerous pieces of equipmenthave been omitted` deliberately `since these can `beadded :thereto by those skilled in the art. Other forms of mixing and .electrical'separation apparatusmay be introduced instead of those set out in the figure. A l n Feed oil ispassed from source 11 byway of line 12 into heater 13. The rfeed -oil-in the process is derivedcfrom crude petroleum and is. described asa virginA petroleum oil. This` oil may be defined as--a distillate having adistinct boiling range within the broad limits of 450 F. and 700 Alparticularly suitable'loil boils `over the range ofabout 500 F. `and 675 F. These oils -inf general are consideredin the petroleum industry-as lightgas oils,` kerosenes, .and distillate'ifuels. :In this embodiment the feed oil was -a virgin oil derived from distillation of crude `petroleum having, the following .physical characteristics:.ASTM distillation I.B.P. 509.F.;.10%, Y540 F.; "%,f5-85 F.; 90%, i636"` F. andend point' 676 F. (on 'a recovered basis); the flash point was 265 COC vland the iire'poi'ntfwas .300 F.; the viscosity was 45.1 SSU at 100;-F. lfheiunsulfonated-residue.Was185.2 weight percent. The Saybolticolor was 16.

.In .fheater 13 which is .shown :here as an vexchanger combined stream from chamber 16 is passed by way of line Zithrough vmixer 22 where an intimate mixture is formed. Ylt ispreferred that the acid be -linely divided droplets dispersed in the oil. Mixer v22. may be any form of mixer which will produce a very ine dispersion of acid in oil; in this embodiment mixer -22 consists of a gate valve type orifice. mixer. The intimate mixture jproduced in mixerZZis passed by Way of line 23 linto a mixer 24. In -thisembodiment mixer 24= is a three `stage mixer provided With a motor driven turbineV 26, l27 and 2S, 11espectively, ineach stage. The turbines aremounted on a commonshaft 29 and arerotated by electrical motor driverl. T he .mixture of treated oil and sludge particles formed by the treatment is passedfrom the lirst stage to the second ,stageby line 32 and from the second -stage and Ythe thirdstage by line 33.

The treating `zone afforded -by mixer 24 may -be v`4any form of mixing device such as yknown in the `acid treating art for providing intimate contact of oil and acid andthe necessary holding time needed to completethe treating of the oil. The treating zone 24 is adapted to maintain the oilat close to the :desired treating temperature. Normally insulating t-he treating zone will permit substantially uniform temperature as the exothermic reaction Will .compensate for losses to the atmosphere from the surface `of the treating zone. In this embodiment mixer 24.is operatedat close to 160 F. i.e., each stageis within 2-3 F. of the desired temperature.

The-oil .and .acid are contactedV in mixer.24 -fo-r a period of, time .between about 10 minutes and 30 minutes. The exact time of contacting is determined by the feed oil and the .product oil characteristics, the amount 4of acid, concentration of acid and also the temperature. VIn thisparticular embodiment operating at close to 160 k1:". the t-otaltime in mixer 24 is 15 minutes as -closely as-it can beheld in such an operation.

A mixture consisting yof treated oil andy .sludge particles is Withdrawn from the third stage of mixer -24 and-is vpassed by way of line 36 into cooler 37. YCooler 37 is Pfand belowcanan economic separation of treated oil and sludge particles be obtained while simultaneously producing the desired product characteristics'with economic acid usage. In general the treated oil-sludge stream from mixer 24 is substantially immediately cooled to a temperature between 70 and 100 F. and more usually between 90 F. and 100 F. In the embodiment shown in the ligure cooler 37 drops the temperature of the stream in line 36 to a temperature just below 100 F. Operation at the maximum temperature is desired in order to maintain a low enough viscosity of the oil to permit easy and fast separation of sludge particles.

The cooled oil-sludge dispersion is passed from cooler 37 by way of line 38 in the electrical sludge separation zone 39. Electrical sludge separation zone 39 is adapted to subject the cooled oil-sludge dispersion to the action of high-voltage electrical field of suicient intensity to coalesce said sludge particles. The separation zone 39 also affords time for the accelerated operation to permit separating a sludge phase by way of line 41 from a treated oil phase by way of line 42; the treated oil phase contains not more than about 0.01 weight percent of sludge. In the particular embodiment described the final product characteristics require that the treated oil phase withdrawn by way of line 42 contain less than 0.01 weight percent of sludge; herein sludge content is about 0.008 weight percent. In general the temperature of operation in sludge zone 39 is about the temperature of the stream from cooler 37.

The treated oil phase is passed by way of line 42 into chamber 43. An aqueous caustic solution from source 46 is passed by way of line 47 in the chamber 43. Aqueous caustic solution 46 may consist of any alkali metal hydroxide dissolved in water. Ordinarily sodium hydroxide is the caustic used. The solution contains enough alkali metal hydroxide to react with the acidic materials present in the treated oil phase and produce a neutralized oil. The amount of caustic used is dependent upon the degree of mixing provided. In general with efficient mixing it has been found that effective neutralization and separation is obtained using about 200% of the theoretical requirement of caustic. While aqueous caustic solutions of the usual concentrations may be used it is preferred to operate with the dilute solutions containing between about and 15 weight percent of caustic. In this embodiment suicient aqueous caustic solution is used to provide 200% of the theoretical requirement for neutralizing the treated oil phase in a 5-6 weight percent caustic solution.

The stream from chamber 43 is passed by way of line 48 through mixer 49, at a temperature between 90 F. and 100 F., and by way of line 51 into electrical solution separation zone 52. Mixer 49 is identical to mixer 22. Electrical solution separation zone is identical in opera tion to separation zone 39. In separation zone 52 the oil-caustic mixture from line 51 is subjected to the action of high-voltage electrical eld of sufficient intensity to coalesce the aqueous droplets i.e. solution particles, present in the oil-caustic mixture from separation zone 52; a spent caustic solution is withdrawn by Way of line 53 and a neutralized oil stream is withdrawn by way of line 54.

The neutralized oil stream from this particular embodi ment contains so very little aqueous haze that a few hours settling time in tankage is suicient to produce a bright oil suitable for commercial sale. In the particular embodiment the neutralized oil from line S4 has an unsulfonated residue of 91.5 percent.

It is to be understood that under some conditions, the neutralized oil may contain an undesirably large amount of aqueous caustic solution. This dispersed solution may be removed by passage through a coalescer such as a salt drum or a bed of alumina particles.

Owing to the substantially immediate cooling carried out in cooler 37 it is possible to obtain in zone 39 separation to the minute sludge content such that no water wash# 4 ing step is needed between zone 39 and zone 52 and the eminently desired result of direct neutralization with little or no emulsion problem is obtained.

The electrical sludge separation zone 39 and electrical solution separation zone 52 are conducted under conditions well known in the electrical separation art. In general the applications and the conditions used in these separation zones may be obtained from the teachings of -U.S. 2,182,145; 2,412,791; 2,447,529; and 2,447,530.

In the particular embodiment described electrical sludge separation zone 39 operates at a voltage of 46,000 volts and electrical solution separation zone 52 operates at 18,000 volts.

In this embodiment the charged oil was eminently suitable for plant spray purposes and as a carrier of insecticides. The acid treatment had changed the ASTM distillation only a little, which distillation had the range i of 500 F. to 660 F. The Saybolt color was 22 and the color stability as measured by an aging test was superior. The ash points and tiring points were unchanged. The ASTM D-235 corrosion was excellent. The viscosity was 42.7 SSU at 100 F. and the unsulfonated residue was 91.5. In all respects an excellent plant spray oil.

Thus having described the invention, what is claimed is:

1. A process for producing a petroleum oil of low sulfonatable-material content which process comprises (a) treating a virgin petroleum oil boiling over the range of 450 F. and 700 F. with sulfuric acid, in intimate mixture, in an amount between about 1 and 1.5 lbs. of acid per gallon of oil, said acid having a concentration of between about 96% and 100%, at a temperature between about 150 F. and 170 F. for a time between about 10 and 30 minutes, (b) substantially immediately after said treating, cooling the mixture of oil and dispersed sludge particles produced in step (a) to a temperature between F. and 100 F., (c) passing said cooled oil-sludge mixture into sludge separation zone wherein said cooled mixture is subjected to the action of a high-voltage electrical eld of suicient intensity to coalesce said sludge particles and separating a sludge phase from a treated oil phase containing not more than about 0.01 weight percent of sludge, and (d) subjecting said treated oil phase to a neutralization operation consisting of (1) intimately mixing said treated oil phase with aqueous caustic solution containing between about 5 and 15 weight percent of caustic in an amount suicient to neutralize the acidic materials present in said treated oil phase at a temperature between F. and 100 F., (2) passing said oil-solution mixture of oil and solution into a solution separation zone wherein said oil-solution mixture is subjected to the action of a high-voltage electrical eld of sufficient intensity to coalesce the solution particles in said oil-solution mixture and separating a solution phase from a neutralized oil.

2. The process of claim 1 wherein said caustic usage is about 200% of the theoretical requirement.

3. A process for making a petroleum oil which is suitable for use as a plant spray oil which process comprises (l) forming an intimate mixture of sulfuric acid, about 98% strength, with a virgin petroleum oil boiling over the range of about 500 F. and 675 F., using about 1.1-1.2 lbs. of acid per gallon of oil and maintaining said mixture for about 15 minutes at close to 160 F., to obtain a dispersion of sludge particles in treated oil, (2) substantially immediately after said time cooling said oilsludge dispersion to between 90 F. and 100 F., (3) in a sludge separation zone subjecting said cooled oil-sludge dispersion to the action of a high-voltage electrical field of suicient intensity to coalesce said sludge particles and separating a sludge phase from a treated oil phase containing less than 0.01 weight percent of sludge, and (4) subjecting saidtreated oil phase to a neutralization operation consisting of (a) forming an intimate mixture of V5 6 weight percent aqueous caustic solution in treated oil phase in an amount of about 200% of the theoretical requirement to neutralize said treated oil phase, at a temperature between 90 F. and 100 F., and (b) in a solution separation zone subjecting the oil-caustic mixture to the action of a high-voltage electrical eld of sufficient intensity to coalesce the aqueous droplets present in said oil-caustic mixture and separating aqueous caustic solution phase from neutralized oil.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS FOR PRODUCING A PETROLEUM OIL OF LOW SULFONATABLE-MATERIAL CONTENT WHICH PROCESS COMPRISES (A) TREATING A VIRGIN PETROLEUM OIL BOILING OVER THE RANGE OF 450*F. AND 700*F. WITH SULFURIC ACID, IN INTIMATETE MIXTURE, IN AN AMOUNT BETWEEN ABOUT 1 AND 1.5 LBS. OF ACID PER GALLON OIL, SAID ACID HAVING A CONCENTRATION OF BETWEEN ABOUT 96% AND 100%, AT A TEMPERATURE BETWEEN ABOUT 150*F. AND 170*F. FOR A TIME BETWEEN ABOUT 10 AND 30 MINUTES, (B) SUBSTNTIALLY IMMEDIATELY AFTER SAID TREATING, COOLING THE MIXTURE OF OIL AND DISPERSED SLUDGE PARTICLES PRODUCED IN STEP (A) TO A TEMPERATURE BETWEEN 70*F. AND 100*F., (C) PASSING SAID COOLED OIL-SLUDGE MIXTURE INTO SLUDGE SEPARATION ZONE WHEREIN SAID COOLED MIXTURE IS SUBJECTED TO THE ACTION OF A HIGH-VOLTAGE ELECTRICAL FIELD OF SUFFICIENT INTENSITY TO COALESCE SAID SLUDGE PARTICLES AND SEPARATING A SLUDGE PHASE FROM A TREATED OIL PHASE CONTAINING NOT MORE THAN ABOUT 0.01 WEIGHT PERCENT OF SLUDGE, AND (D) SUBJECTING SAID TREATED OIL PHASE TO A NEUTRALIZATION OPERATION CONSISTING OF (1) INTIMATELY MIXING SAID TREATED OIL PHASE WITH AQUEOUS CAUSTIC SOLUTION CONTAINING BETWEEN ABOUT 5 AND 18 WEIGHT PERCENT OF CAUSTIC IN AN AMOUNT SUFFICIENT TO NEUTRALIZE THE ACIDIC MATERIAL PRESENT IN SAID TREATED OIL PHASE AT A TEMPERATURE BETWEEN 90*F. AND 100*F., (2) PASSING SAID OIL-SOLUTION MIXTURE OF OIL AND SOLUTION INTO A SOLUTION SEPARATION ZONE WHEREIN SAID OIL-SOLUTION MIXTURE IS SUBJECTED TO THE ACTION OF A HIGH-VOLTAGE ELECTRICAL FIELD OF SUFFICIENT INTENSITY TO COALSESCE THE SOLUTION PARTICLES IN SAID OIL-SOLUTION MIXTURE AND SEPARATING A SOLUTION PHASE FROM A NEUTRALIZED OIL. 